This nonprovisional application claims priority under 35 U.S.C. xc2xa7 119(a) on Patent Application No(s). 091121427 filed in TAIWAN, R.O.C. on Sep. 19, 2002, which is (are) herein incorporated by reference.
1. Field of the Invention
The present invention relates to a brushless motor structure for a vehicle, and in particular to the brushless motor structure having ferromagnetic steel elements disposed on a wheel of a vehicle.
2. Description of the Related Art
A conventional motor-driven bicycle usually uses a chain driven by a motor to rotate the wheels. However, the gears of the conventional bicycle are small and have fewer teeth. The levers acting on the wheels are also shorter, such that the output power of motors must be larger to provide enough torque to drive the bicycle. Furthermore, permanent magnets are used to be magnetic poles of the conventional motor-driven bicycles. When power runs out, permanent magnets cause counter-electromotive force (CEMF). Hence, the load increases, and the user is required to exert more energy to power the conventional motor-driven bicycle.
Accordingly, an object of the invention is to provide a brushless motor structure for a vehicle, such as a motor-driven bicycle. Although the motor has a simple structure, it can provide larger output torque. Moreover, when the battery of the vehicle is exhausted, the user can power the vehicle without an increase in load.
The present invention provides a brushless motor for a vehicle. The vehicle has a plurality of electromagnets connected to the body and a wheel with ferromagnetic steel elements annularly disposed on the wheel. Each electromagnet provides an opening through which the wheel travels. When the wheel rotates, at least one steel element is magnetically charged. The electromagnets attract the at least one steel element to pass through the gap, thus maintaining wheel rotation. s
In a preferred embodiment, the wheel has a rim. The steel elements are secured on the rim. The brushless motor further has a battery electrically connected to the electromagnets.
Furthermore, the steel elements are disposed on the rim with the same first angular intervals, and the electromagnets are disposed on the main body with the same second angular intervals. The first angular intervals are not equal to the second angular intervals. The ratio of the first angular intervals and the second angular intervals can be 3:2.
The present invention also provides a motor-driven bicycle using the brushless motor above.
A detailed description is given in the following embodiments with reference to the accompanying drawings.